Fix embed thread quitting too early

src/bootstrap.js

@@ -1,6 +1,26 @@
+// setImmediate and process.nextTick makes use of uv_check and uv_prepare to
+// run the callbacks, however since we only run uv loop on requests, the
+// callbacks wouldn't be called until something else activated the uv loop,
+// which would delay the callbacks for arbitrary long time. So we should
+// initiatively activate the uv loop once setImmediate and process.nextTick is
+// called.
+function wrapWithActivateUvLoop(func) {
+  return function() {
+    process.activateUvLoop()
+    return func.apply(this, arguments)
+  }
+}
+
 (function bootstrap(NativeModule) {
+  // Make async method work.
+  const timers = NativeModule.require('timers')
+  process.nextTick = wrapWithActivateUvLoop(process.nextTick)
+  global.setImmediate = wrapWithActivateUvLoop(timers.setImmediate)
+  global.setTimeout = wrapWithActivateUvLoop(timers.setTimeout)
+  global.setInterval = wrapWithActivateUvLoop(timers.setInterval)
+
   // Turn our modules into built-in modules.
-  let exports = this
+  const exports = this
   NativeModule._source.asar_archive = exports.asar_archive
   NativeModule._source.asar_monkey_patch = exports.asar_monkey_patch
   NativeModule._source.pickle = exports.pickle

src/node_integration.cc

@@ -10,6 +10,7 @@
 #include "node/deps/uv/src/uv-common.h"
 #include "node/src/env-inl.h"
 #include "node/src/node.h"
+#include "node/src/node_internals.h"
 
 namespace yode {
 
@@ -30,12 +31,17 @@ NodeIntegration::~NodeIntegration() {
   // Clear uv.
   uv_sem_destroy(&embed_sem_);
   uv_close(reinterpret_cast<uv_handle_t*>(&wakeup_handle_), nullptr);
+  uv_close(reinterpret_cast<uv_handle_t*>(&next_tick_handle_), nullptr);
 }
 
 void NodeIntegration::Init() {
-  // Handled used for waking up the uv loop in embed thread.
+  // Handle used for waking up the uv loop in embed thread.
+  // Note that we does not unref this handle to keep the active_handles > 0.
   uv_async_init(uv_loop_, &wakeup_handle_, nullptr);
-  uv_unref(reinterpret_cast<uv_handle_t*>(&wakeup_handle_));
+
+  // Handle used for invoking CallNextTick.
+  uv_async_init(uv_loop_, &next_tick_handle_, &OnCallNextTick);
+  uv_unref(reinterpret_cast<uv_handle_t*>(&next_tick_handle_));
 
   // Start worker that will interrupt main loop when having uv events.
   uv_sem_init(&embed_sem_, 0);
@@ -62,6 +68,14 @@ void NodeIntegration::UvRunOnce() {
   uv_sem_post(&embed_sem_);
 }
 
+void NodeIntegration::CallNextTick() {
+  uv_async_send(&next_tick_handle_);
+}
+
+void NodeIntegration::ReleaseHandleRef() {
+  uv_unref(reinterpret_cast<uv_handle_t*>(&wakeup_handle_));
+}
+
 void NodeIntegration::WakeupMainThread() {
   PostTask([this] {
     this->UvRunOnce();
@@ -102,4 +116,21 @@ void NodeIntegration::EmbedThreadRunner(void *arg) {
   }
 }
 
+// static
+void NodeIntegration::OnCallNextTick(uv_async_t* handle) {
+  // Get current env.
+  v8::Isolate* isolate = v8::Isolate::GetCurrent();
+  v8::HandleScope handle_scope(isolate);
+  node::Environment* env = node::Environment::GetCurrent(isolate);
+  CHECK(env);
+
+  // The InternalCallbackScope can handle everything for us.
+  v8::Context::Scope context_scope(env->context());
+  node::InternalCallbackScope scope(
+      env,
+      v8::Local<v8::Object>(),
+      {0, 0},
+      node::InternalCallbackScope::kAllowEmptyResource);
+}
+
 }  // namespace yode

src/node_integration.h

@@ -25,6 +25,12 @@ class NodeIntegration {
   // Run the libuv loop for once.
   void UvRunOnce();
 
+  // Handle the nextTick callbacks.
+  void CallNextTick();
+
+  // Release our ref to uv handle, so active handles count become 0.
+  void ReleaseHandleRef();
+
  protected:
   NodeIntegration();
 
@@ -45,14 +51,20 @@ class NodeIntegration {
 
  private:
   // Thread to poll uv events.
-  static void EmbedThreadRunner(void *arg);
+  static void EmbedThreadRunner(void* arg);
+
+  // Handle nextTick callbacks.
+  static void OnCallNextTick(uv_async_t* handle);
 
   // Whether the libuv loop has ended.
   bool embed_closed_;
 
   // Handle to wake up uv's loop.
   uv_async_t wakeup_handle_;
 
+  // Handle to call nextTick callbacks.
+  uv_async_t next_tick_handle_;
+
   // Thread for polling events.
   uv_thread_t embed_thread_;
 

src/yode.cc

@@ -36,6 +36,11 @@ void Log(const v8::FunctionCallbackInfo<v8::Value>& args) {
   }
 }
 
+// Force running uv loop.
+void ActivateUvLoop(const v8::FunctionCallbackInfo<v8::Value>& args) {
+  g_node_integration->CallNextTick();
+}
+
 // Invoke our bootstrap script.
 void Bootstrap(const v8::FunctionCallbackInfo<v8::Value>& args) {
   node::Environment* env = node::Environment::GetCurrent(args);
@@ -61,10 +66,10 @@ bool InitWrapper(node::Environment* env) {
   // Initialize GUI after Node gets initialized.
   v8::HandleScope handle_scope(env->isolate());
   Init(env);
-  // process.log = Log
+  // Native methods.
   env->SetMethod(env->process_object(), "log", &Log);
-  // process.bootstrap = Bootstrap
   env->SetMethod(env->process_object(), "bootstrap", &Bootstrap);
+  env->SetMethod(env->process_object(), "activateUvLoop", &ActivateUvLoop);
   // versions = process.versions
   v8::Local<v8::Value> versions = env->process_object()->Get(
       env->context(), ToV8(env, "versions")).ToLocalChecked();
@@ -74,13 +79,18 @@ bool InitWrapper(node::Environment* env) {
   return true;
 }
 
-// Run uv loop for once before entering GUI message loop.
 bool RunLoopWrapper(node::Environment* env) {
+  // Run uv loop for once before entering GUI message loop.
   if (g_first_runloop) {
     g_node_integration->UvRunOnce();
     g_first_runloop = false;
   }
-  return RunLoop(env);
+  // Run GUI message loop.
+  RunLoop(env);
+  // No need to keep uv loop alive.
+  g_node_integration->ReleaseHandleRef();
+  // Enter uv loop to handle unfinished uv tasks.
+  return uv_run(env->event_loop(), UV_RUN_DEFAULT);
 }
 
 }  // namespace

src/yode.h

@@ -19,7 +19,7 @@ int Start(int argc, char* argv[]);
 void Init(node::Environment* env);
 
 // Run the GUI message loop for once, implemented by different platforms.
-bool RunLoop(node::Environment* env);
+void RunLoop(node::Environment* env);
 
 }  // namespace yode
 

src/yode_linux.cc

@@ -13,9 +13,8 @@ void Init(node::Environment* env) {
   gtk_init(nullptr, nullptr);
 }
 
-bool RunLoop(node::Environment* env) {
+void RunLoop(node::Environment* env) {
   gtk_main();  // block until quit
-  return uv_run(env->event_loop(), UV_RUN_DEFAULT);
 }
 
 }  // namespace yode

src/yode_mac.mm

@@ -14,9 +14,8 @@ void Init(node::Environment* env) {
   [NSApp setActivationPolicy:NSApplicationActivationPolicyRegular];
 }
 
-bool RunLoop(node::Environment* env) {
+void RunLoop(node::Environment* env) {
   [NSApp run];  // block until quit
-  return uv_run(env->event_loop(), UV_RUN_DEFAULT);
 }
 
 }  // namespace yode

src/yode_win.cc

@@ -14,13 +14,12 @@ void Init(node::Environment* env) {
 #endif
 }
 
-bool RunLoop(node::Environment* env) {
+void RunLoop(node::Environment* env) {
   MSG msg;
   while (::GetMessage(&msg, NULL, 0, 0)) {
     ::TranslateMessage(&msg);
     ::DispatchMessage(&msg);
   }
-  return uv_run(env->event_loop(), UV_RUN_DEFAULT);
 }
 
 }  // namespace yode

yode.gyp

@@ -24,6 +24,7 @@
         '.',
         'node/deps/cares/include',  # for ares.h
         'node/deps/uv/include',  # for uv.h
+        'node/src',  # for node things
       ],
       'defines': [
         'NODE_WANT_INTERNALS=1',